Personally, I'd go for the 4 valve RS. I have one, and it's my favorite ride. Not as cool as a naked bike, but not as hot as an RT.
Power is nice on the RS, and is pretty smooth between 3500 and 5000rpm. Gets a little buzzy above that, but in 5th that is asking to talk to a cop.
ABS might get you a discount on your insurance. I've only triggered it once in about 60,000 miles, and I'm not sure that locking up the rear wheel in that particular situation would have been disasterous.
I have read all the hype on the Paralever, but honestly can't tell the difference between my bikes with it and those with the Monolever. As far as I can tell, the "jacking" force of the monolever rear end merely counters the squat caused by weight transfer under hard acceleration. The only time I have ever seen the "jacking" action is in dyno videos where there is no weight transfer when the rear wheel accelerates because the bike remains stationary. Downside is that doing a spline lube is about twice as much work.
The 4 valve engine has the Motronic ECU which has some self diagnostic capability not available with the earlier Jetronic system. It also gets rid of the MAF, and as a result seems to have better throttle response. I also get about 10% better fuel efficiency over my Jetronic equipped bikes.
Last, the RS has bigger brakes and tires, the seat feels a bit lower, and there are fewer problems with the center stand rusting out. There is a tendency for the headers to crack where they enter the muffler. That's easy to prevent by putting a jubilee clamp around them about 5-6 inches ahead of the muffler.
